1. Field of the Invention
The present invention is directed to a Fault Tolerant Recoverable TCP/IP Connection Router (FTR-CR) and methods of connecting at least two FTR-CRs to multiple systems, where the FTR-CRs have synchronized internal tables and are capable of switching between active and standby states.
2. Discussion of the Prior Art
A conventional Transport Control Protocol/Internet Protocol connection router (TCP-CR) connects clients making requests to servers that satisfy the requests. The requests are configured as IP packets for transport in a system running TCP/IP, such as the Internet. The TCP-CR forwards TCP/IP connection requests to multiple servers based on workload capacity information, server capabilities, balancing algorithms and availability of the servers.
For proper operation, the TCP-CR examines all IP packets on the way from the clients to the servers, and keeps track of all established connections. The TCP-CR appears to any previous hop router as the last hop. In addition, the TCP-CR appears to clients as the end point of all the TCP connections.
Problems arise when the TCP-CR fails as described below. Conventional IP recovery mechanisms for recovery of a failed TCP-CR include address resolution protocol (ARP) aging, and various routing protocols. Additional conventional recovery mechanisms require either a shared recoverable file system to store state information, or the reconstruction of host connection information by the systems in the cluster of servers.
These conventional recovery schemes are slow to recover for new connections, do not recover existing connections, and do not recover for reach-ability failures as defined below. Consequently, conventional IP recovery mechanisms do not provide a complete solution to TCP-CR failures.
Accordingly, there is a need for a TCP-CR failure recovery scheme which is fast and efficient, allows quick recovery for both new and existing connections, and recovers for reach-ability failures.